In a smaller bowl, whisk together mashed bananas, Greek yogurt and vanilla extract until smooth and all lumps are gone. Pour over dry ingredients and mix well.

Using a round cookie cutter (or shape with your hands), spoon mixture into the cutter pressing firmly then removing the cutter. Shape should keep form; do this until you have 20 cookies or you run out of batter. Bake at 350 degrees F for about 15 to 20 minutes and enjoy!